This invention relates generally to the field of renewable fuel productions and more specifically to a process for the production of ethanol by use of a vacuum process and selectively permeable membranes to increase ethanol production efficiency.
Production of ethanol is an age old technology that has lacked development throughout the centuries. In both traditional ethanol production (wine making, etc) and commercial ethanol production yeast, a facultative anaerobe, is placed in a solution of sugar or fermenting mash that is open in some way to oxygen. The yeast is allowed to ferment the sugars (glucose) into ethanol until the concentration of ethanol to fermenting mash reaches approximately 15%, at which, the enzyme in the yeast that converts sugar to ethanol is destroyed or denatured due to the high concentration of ethanol and hence ceasing ethanol production. Ethanol production is both more time consuming and only partially efficient.
To overcome some obstacles in ethanol production, such as random strains of bacteria ruining the ethanol production process, traditional and commercial ethanol producers sanitize all the equipment used in ethanol production in some way (usually through the use of an iodine solution) to ensure that ethanol and not vinegar will be produced. This has helped to improve the efficiency of ethanol production. Ethanol production ceases once the concentration of ethanol to fermenting mash reaches approximately 15%. To overcome this barrier, some producers have experimented with different strains of yeast or genetically altered yeast to produce high tolerance yeast that can continue to produce ethanol until the concentration of ethanol to fermenting mash reaches approximately 18% to 20%. Basically, the yeast that produces ethanol has a higher tolerance to ethanol concentrations and will not denature until a concentration of approximately 18% to 20% has been reached but this form of improvement (yeast being tolerant to ethanol) is limited.
Deficiencies in prior technology include the presence of oxygen in the fermenting mash, either at the surface of the mash or dissolved within the mash, and the fact that the yeast is directly exposed to the fermenting mash. When yeast has oxygen available to it, it will go through cellular respiration rather than alcoholic fermentation, hence making ATP (adenosine triphosphate) instead of ethanol.
Accordingly, it is desirable to design and develop new methods and systems for increasing the efficiency in the ethanol producing process.